1. Field of the Invention
The present invention relates to a processing method of a metal product surface; and more specifically to methods for preventing a metal product surface from rusting, inhibiting static electricity on a metal product surface from discharging, and providing adiabaticity to a metal product surface.
2. Description of the Related Art
Model changes are carried out often in the field of metal products such as conveyance including an automobile, an electric train, an aircraft, a bus, and a ship; iron and steel products including a bridge, an iron plate, an iron pole, and a guardrail; household products including a laundry rack, a handle, and a wagon; water-related products including a faucet; and agricultural machines including a tractor and a cultivator. The preference of users changes with the lapse of time, and the purpose of the model changes is to cope with the changes of the preference.
It has heretofore been known that, when the design of a metal product is changed for example, a metal plate material constituting the surface is processed into a desired shape (for example, Patent Document 1). It has not been easy, however, to change the appearance of a metal product after it had once been processed.
Further, a metal product of recent years has a better durability than a conventional one; and frequently continues to be used for a long period of time depending on the maintenance on the side of manufacturers and the usage by users. On this occasion, surface treatment of forming a film (for example, Patent Documents 2 and 3) or applying plating of chromium, a transition metal, or the like (for example, Patent Document 4) is applied in order to prevent the deterioration of physical properties or damages caused by the corrosion of a metal product surface. However, a film and plating always have possibilities of breakage, cracking, and exfoliation caused by an impact, and efforts have been made still now to reduce the possibility of corrosion and prevent surface damages by devising the type of a chemical compound used as such a film or the type of metal used for plating.
Furthermore, a technology of applying an anticorrosive paint composition to the surface of a metal product (Patent Documents 5 and 6) and a technology of drawing a design on a surface with paint have been known well. The technologies however have: not only the cumbersomeness of the complicated operation process and the necessity of many process steps until finishing, a high susceptibility to the damages of a metal product surface during coating, or requirement of proficiency for beautifully finishing a coated surface; but also the problems of the cracking and exfoliation of paint. Consequently, in an automobile for example, it has been necessary to apply washing and waxing to a coated surface very frequently.
Moreover, in the conventional surface treatment such as plating and coating, once the surface treatment has been applied, a pattern or the like formed on the surface cannot be changed easily. Further, in the conventional processing technology of a metal surface, generally a surface is smoothened from the viewpoint of removing stains more easily in the event of washing and therefore the designability of a metal product has been restricted also from this viewpoint.
In addition, since a metal has a good electric conductivity, electric charge (static electricity) accumulated in a human body particularly under a low-temperature low-humidity environment such as during winter season causes feeling of discomfort or fear such as zap when electric discharge occurs by touching a metal product, and various goods have been proposed in order to prevent such feeling. Furthermore, another drawback is that, since a metal has a high thermal conductivity, one may suffer burns if one carelessly touches a heated metal product such as a faucet for serving hot water or a kettle for boiling water. All the contents disclosed in the following documents are incorporated herein by reference.